I have a bmw 330 ci and it is a 2001, i ve had it for two years.?

my problem is whenever it is cold the car won't start. and if it is a warm day it starts right away, this certified bmw mechanic changed the alternator, the battery and the last thing the spark plugs and i still have the same problem and now he is thinking about messing with the fule pump. thank you for your answers.

I have a bmw 330 ci and it is a 2001, i ve had it for two years.?firewall

First of all I'm a little skeptical of the mechanic. If the symptoms described are accurate, and the car cranks, then it's not the battery. The battery only turns the engine over. The alternator doesn't have anything to do with the starting of the car. The alternator merely recharges the battery when the engine is running.

I doubt if it was the spark plugs since plugs last for quite a while and worn plugs will give other signs (poor performance, bad gas mileage, etc) before refusing to start the car.

There can be any number of things wrong. Yes it might be a fuel pump. But pumps are expensive and you should be pretty sure this is the problem before replacing something that's probably good. The MAS might be faulty. Could also be the VANOS. Or a loss wire.

Sorry I can't be more specific, but trying to diagnose an auto problem over the internet is difficult.

But again, you might want to seek out another BMW mechanic.